OF DENISON UNIVERSITY. 
23 
PRODUCTUS NODOCOSTATUS, Sp. n. 
pi . isr , - t c, . ^ 
Shell of rather small size, sub-circular in outline, only moderately 
convex. 
Ventral valve as wide as long; hinge line equalling seven-tenths 
the greatest width ; ears small, triangular ; beak slightly projecting, 
acutely prominent, sloping sharply to the flat ears, sloping gently to 
the front margin ; surface covered by numerous, coarse, rounded, rare- 
ly bifurcating radiating costae, rendered nodose by equally coarse, con- 
centric wrinkles. A few spines could be detected on the ears in some 
specimens, but in others they are obscure. If this is a Productus it is 
quite remarkable in its surface marking and also in its slight convexity. 
Width, 12 mm., length, ii mm., convexity, 5 mm., or less. We 
have been unable to compare specimens of P. morbillina. Win. which 
seems to resemble it. From the upper layers at Rushville, about 100 
feet above conglomerate II. 
RHYNCHONELLA CONTRACTA, H. 
(Plate XI, Fig. 21.) 
Since the last volume of the bulletin was published, we have had 
opportunity to compare carefully and minutely specimens in the same 
state of preservation, preserving both valves, teeth and all details from 
the Chemung of Chatauqua Co., and the Waverly of Medina Co., and 
find the most perfect identity of characters. There can be no doubt 
of the identification. The same species is also doubtfully known from 
the Cuyahoga shales. 
RHYNCHONELLA MARSHALLENSIS, Win. 
This is the common species in the middle Waverly, but occurs 
rarely seventy feet below conglomerate I near Granville, and in Ash- 
land county. Whether this species is but a modification of R. sappho 
must be left undecided. The specimens referred to R. sappho in the 
last paper are more closely allied to the present form than then sup- 
posed. 
RYHNCHONELLA, Sp. 
(Plate XI, Fig. 22.) 
We have a small specimen from Lodi which seems to differ from 
all the Waverly species, though almost a minature of R. marshallensis. 
